JP2001152034A - Silicon-based flame retardant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flame-retardant for polycarbonate capable of imparting excellent flame-retardancy and thermal stability to the polycarbonate. SOLUTION: The objective flame-retardant is a silicon-based flame-retardant expressed by formula (1) (R1 to R6 are each independently a 1-20C univalent hydrocarbon group; Ar is a 6-20C bivalent aromatic group; (a) to (f) are each 0 or 1; and the number-average value of (n) is >=1).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a silicon-based flame retardant. More specifically, the present invention relates to a silicon-based flame retardant capable of imparting excellent flame retardancy and thermal stability.

[0002]

2. Description of the Related Art Polymers such as synthetic resins and elastomers are:
Compared to glass and metal, it has excellent moldability and impact resistance, and is therefore used in various fields including automotive parts, home electric parts, and OA equipment parts. However, since the application of the polymer is limited by its flammability, various flame retarding methods have been proposed.

As a method for making a polymer flame-retardant, a method of adding a halogen-based, phosphorus-based, or inorganic flame retardant to a polymer is known. However, halogen-based flame retardants include:
There is a concern about environmental problems such as generation of acid gas during combustion, which may damage the combustion furnace or cause acid rain, and poor recyclability. In addition, phosphorus-based flame retardants are easily hydrolyzed, and when a molded article containing the same is exposed to wind and rain, the flame retardants dissolve and cause eutrophication,
There are problems such as lack of recyclability. Furthermore, polymers using phosphorus or inorganic flame retardants have thermal stability, impact strength,
Since the molding fluidity and heat resistance are not always satisfactory, industrial applications of the polymer have been narrowed.

[0004] In recent years, the demand for fire safety has been intensified in recent years, and further advanced flame retardant technology has been developed. On the other hand, however, environmental problems and mechanical properties of the polymer have been accompanied. There was a problem of a decline. In order to solve this problem, a flame retarding technique using a silicon-containing flame retardant that does not have the above-mentioned problems has been developed.

As one example of the silicon-based flame retardant, silicone such as dimethyl silicone or silicone resin is known. Flame-retardant resin compositions containing silicones and silicone resins have been used for practical use due to poor flame retardancy, although the recyclability and environmental issues such as halogen-based and phosphorus-based flame retardants have been solved. I can't stand it.

[0006] As another example of the silicon-based flame retardant, an organic silicate compound is known. For example, a flame-retardant composition comprising an aromatic polycarbonate and a silicate resin is disclosed (EP 415070A2: corresponding to JP-A-3-143951). However, since the organic silicate resin has a branched / crosslinked structure, the dispersibility of the resin intended to impart flame retardancy is poor, and the performance as a flame retardant is not sufficient.

A flame-retardant resin composition comprising polycarbonate resin / polymethylethoxysiloxane / titanium oxide / polytetrafluoroethylene / halogen-based flame retardant / thermoplastic elastomer (Japanese Patent Application Laid-Open No. 9-11110)
No. 9) is known.

In the above composition, an organoalkoxypolysiloxane is used as a flame retardant, which does not contain aromatic groups and thus lacks stability such as water resistance and cannot be put to practical use. .

[0009]

SUMMARY OF THE INVENTION In view of such circumstances, an object of the present invention is to provide a silicon-based flame retardant which does not have the above-mentioned problems, that is, which can impart excellent flame retardancy. Is what you do.

[0010]

Means for Solving the Problems As a result of diligent studies on silicon-based flame retardants, the present inventors have found that a silicon-based flame retardant having a specific structure surprisingly has a high polymer stability while maintaining thermal stability. The inventors have found that the flame retardancy is dramatically improved, and completed the present invention.

That is, the present invention provides a silicon-based flame retardant represented by the following formula (1).

[0012]

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(Wherein, R ^{1 to} R ⁶ are each independently a monovalent C
Represents a hydrocarbon group having ₁ -C _20, Ar represents a divalent aromatic group C ₆ -C _20, a to f is 0 or 1, and n
Is 1 or more when represented by a number average n value. )

Hereinafter, the present invention will be described in detail. The present invention relates to (A) a silicon-based flame retardant having a specific structure, and excellent flame retardancy can be imparted by blending the flame retardant with the polymer (B). Here, (A)
Is important to have a silicon atom. Due to the presence of silicon atoms, a silica coating is formed during combustion and flame retardancy is improved.

(A) must contain an aromatic group. The aromatic silicon-containing flame retardant has improved compatibility with (B) especially the aromatic-containing polymer, and (A) is finely dispersed in (B). Found to improve.

Next, it is important that (A) is linear. By being linear, the molecular motion of (A) is activated during combustion and the compatibility with (B) is improved, so that the reaction between the silicon-based flame retardant and the polymer during combustion is promoted. . In addition, since silicon atoms are elements having low surface energy, they tend to segregate on the surface of the composition.
Is linear, the mobility is promoted, so that the silicon-based flame retardant has a concentration distribution on the surface. As a result, when the resin molded body using the flame retardant of the present invention burns, a high concentration of the flame retardant is present on the surface, and excellent flame retardancy is exhibited. In particular, the average concentration C1 (%) of silicon atoms by X-ray photoelectron spectroscopy and the average concentration C2 (%) of silicon atoms of the entire molded body by X-ray fluorescence from the surface of the molded body to a depth of 50 A (angstrom). And the ratio, C
It has been found that when 1 / C2 is 2 to 100, an excellent flame retardant material is obtained, and the present invention has been completed.

In the present invention, (A) is represented by the following formula (1)
In particular, it is preferable that R ^{1 to} R ⁶ are each independently a monovalent C ₆ -C ₂₀ aromatic group.

[0018]

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Wherein R ^{1 to} R ⁶ are each independently a monovalent C
Represents a hydrocarbon group having ₁ -C _20, Ar represents a divalent aromatic group C ₆ -C _20, a to f is 0 or 1, and n
Is 1 or more when represented by a number average n value. )

Among the flame retardants of the present invention, R ^{1 to} R ⁶ are phenyl groups, Ar is 2,2′-bis (1,4-phenylene) propane, and a to f are 0 or 1 simultaneously. The silicon-based flame retardant represented by the following formula (2) or (3) is most preferable.

[0021]

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[0022]

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The (A) flame retardant for polycarbonate of the present invention preferably has a kinematic viscosity at 25 ° C. specified in JIS-K2410 of 100 centistokes or more, more preferably 300 centistokes or more. If the kinematic viscosity is less than 100 centistokes, it becomes volatile and may not be preferable. Further, n which is an index of the degree of polymerization is 1
Or 2 is preferred.

Further, a plurality of flame retardants satisfying the requirements of the present invention can be combined. In particular, it is preferable to use a flame retardant containing a phenyl group at 50 mol% or more and a flame retardant containing a phenyl group at less than 50 mol%.

The polymer which can be made flame-retardant by using the flame retardant of the present invention is a rubber-like polymer, a thermoplastic resin, a thermosetting resin or the like. Plastic resins are preferred.

In the present invention, the thermoplastic resin which is the most preferable polymer in (B) is not particularly limited as long as it is compatible with or homogeneously dispersed in (A). For example, polycarbonates, polystyrenes, polyphenylene ethers, polyolefins, polyvinyl chlorides, polyamides, polyesters, polyphenylene sulfides, polymethacrylates and the like can be used alone or in combination of two or more. In particular, among thermoplastic resins, a resin composition containing a polycarbonate, polystyrene-based or polyphenylene ether-based thermoplastic resin is preferable, and a resin composition mainly containing polycarbonate is particularly preferable.

In the present invention, the polycarbonate in (B) (hereinafter referred to as PC) is not limited as long as it is a resin containing a carbonate group, but is preferably an aromatic polycarbonate, and more preferably an aromatic homopolycarbonate and an aromatic copolycarbonate. You can choose more. The production method includes a phosgene method in which phosgene is blown into a bifunctional phenolic compound in the presence of a caustic alkali and a solvent, or a transesterification method in which a bifunctional phenolic compound is transesterified with diethyl carbonate in the presence of a catalyst. Can be mentioned. The aromatic polycarbonate preferably has a viscosity average molecular weight of 10,000 to 100,000. Here, the bifunctional phenol compound is 2,2'-bis (4-hydroxyphenyl) propane, 2,2'-bis (4-hydroxy-3,5-dimethylphenyl) propane, bis (4-hydroxyphenyl) propane. Phenyl) methane, 1,
1′-bis (4-hydroxyphenyl) ethane, 2,
2′-bis (4-hydroxyphenyl) butane, 2,
2'-bis (4-hydroxy-3,5-diphenyl) butane, 2,2'-bis (4-hydroxy-3,5-dipropylphenyl) propane, 1,1'-bis (4-hydroxyphenyl) Cyclohexane, 1-phenyl-1,
1'-bis (4-hydroxyphenyl) ethane and the like, and 2,2'-bis (4-hydroxyphenyl) propane [bisphenol A] is particularly preferable. In the present invention, the bifunctional phenolic compounds may be used alone or in combination.

In the present invention, one of the styrene resins of the thermoplastic resin (B) is a rubber-modified styrene resin and / or a non-rubber-modified styrene resin, particularly a rubber-modified styrene resin alone or a rubber-modified styrene resin. It is preferable that the resin comprises a rubber-based non-modified styrene resin and
There is no particular limitation as long as it is compatible or uniformly dispersed with (A). The rubber-modified styrene-based polymer refers to a polymer in which a rubber-like polymer is dispersed in a matrix in a matrix composed of a vinyl aromatic-based polymer, and an aromatic vinyl-based polymer is present in the presence of a rubber-like polymer. The monomer and, if necessary, a vinyl monomer copolymerizable therewith are added to obtain a monomer mixture by a known polymerization method such as bulk polymerization, emulsion polymerization and suspension polymerization.

Examples of such a polymer include impact-resistant polystyrene (HIPS), ABS polymer (acrylonitrile-butadiene-styrene copolymer), AAS polymer (acrylonitrile-acryl rubber-styrene copolymer), AES polymer (acrylonitrile-ethylene propylene rubber-styrene copolymer) and the like.

In the present invention, one polyphenylene ether-based resin (B) is a polyether having an aromatic ring in the main chain.

Specific examples of the polyphenylene ether resin include poly (2,6-dimethyl-1,4-phenylene ether), 2,6-dimethylphenol and 2,3,6-trimethylphenol. Is preferred, and poly (2,6-dimethyl-1,4-phenylene ether) is particularly preferred.

In the present invention, the one polyolefin resin (B) is a partially or completely crosslinked thermoplastic polymer composed of a crosslinkable rubbery polymer and a polyolefin. It can be produced by dynamically crosslinking in the presence of an auxiliary.

In the present invention, one rubber-like polymer (B) preferably has a glass transition temperature (Tg) of -30 ° C. or lower. Examples of such a rubber-like polymer include polybutadiene, Poly (styrene-butadiene),
Diene rubbers such as poly (acrylonitrile-butadiene), and saturated rubbers obtained by hydrogenating the diene rubbers, acrylic rubbers such as isoprene rubber, chloroprene rubber, polybutyl acrylate and the like, ethylene-propylene copolymer rubber, ethylene-propylene rubber Examples include crosslinked rubber or non-crosslinked rubber such as diene monomer terpolymer rubber (EPDM) and ethylene-octene copolymer rubber, and thermoplastic elastomer containing the above rubber component.

Among the above thermoplastic elastomers, a polystyrene-based thermoplastic elastomer is particularly preferable, and a block copolymer comprising an aromatic vinyl unit and a conjugated diene unit, or the conjugated diene unit portion is partially hydrogenated or epoxy-modified. Block copolymer and the like.

When the flame retardant of the present invention is added to (B), desirably, (C) as a flame retardant aid other than (A), silicon-based, metal salt-based, halogen-based, phosphorus-based, and nitrogen-based Alternatively, at least one selected from inorganic, fibrous flame retardants, and char formers can be blended.

The silicon-based flame retardants other than the above (A) include (A)
It is a flame retardant containing a silicon element such as a polyorganosiloxane represented by silicone, organic silicate, silica or the like. Polyorganosiloxanes are classified into oils, resins, and rubbers according to their properties. The polyorganosiloxane includes M units represented by monofunctional R ₃ SiO _1/2 , D units represented by difunctional R ₂ SiO, and trifunctional R ₁ SiO
R ₅ (R ₆₎ containing a T unit represented by _3/2 , a Q unit represented by tetrafunctional SiO ₂ , and alkoxy or aryloxy.
O) A linear polyorganosiloxane having a branched structure or a silicone resin having a three-dimensional network structure, which can be obtained by combining structural units of SiO _2.0 (X unit) and (R ₇ O) ₂ SiO _3.0 (Y unit). The rubber is a vulcanized product of a high molecular weight type gum-like linear polydiorganosiloxane. Other polyorganosiloxanes include:
Examples include a modified polyorganosiloxane modified with an epoxy, amino, mercapto, methacryl group, or the like, a polycarbonate (PC) -silicone copolymer, an acrylic rubber-silicone composite, and the like.

The metal salt flame retardant as (C) is, for example, a metal salt of an organic sulfonate such as potassium trichlorobenzenesulfonate, potassium perfluorobutanesulfonate, potassium diphenylsulfon-3-sulfonate, or aromatic sulfone. Polystyrene sulfonic acid in which a metal sulfonate, a metal sulfate, a metal phosphate, or a metal borate is bonded to an imide metal salt or an aromatic ring of an aromatic group-containing polymer such as a styrene polymer or polyphenylene ether. It is a metal salt-based flame retardant such as an alkali metal salt. Such a metal salt-based flame retardant promotes a decarboxylation reaction at the time of combustion, particularly when polycarbonate is used as a polymer, to improve flame retardancy. Further, in the case of the alkali metal polystyrene sulfonate, the metal sulfonate itself becomes a cross-linking point during combustion and greatly contributes to the formation of a carbonized film.

The halogen-based flame retardant (C) is
Halogenated bisphenols, aromatic halogen compounds, halogenated polycarbonates, halogenated aromatic vinyl polymers, halogenated cyanurate resins, halogenated polyphenylene ethers, and the like, preferably decabromodiphenyl oxide, tetrabromobisphenol A, tetrabromo Oligomer of bisphenol A, brominated bisphenol-based phenoxy resin, brominated bisphenol-based polycarbonate, brominated polystyrene,
Brominated cross-linked polystyrene, brominated polyphenylene oxide, polydibromophenylene oxide, decabromodiphenyl oxide bisphenol condensate, halogen-containing phosphoric acid ester, fluorine resin and the like.

As the phosphorus-based flame retardant in the above (C),
Organic phosphorus compounds, red phosphorus, inorganic phosphates and the like can be mentioned.

Examples of the above organic phosphorus compounds include phosphine, phosphine oxide, biphosphine, phosphonium salt, phosphinate, phosphate, phosphite and the like. More specifically, triphenyl phosphate, methyl neopentyl phosphite, pentaerythritol diethyl diphosphite, methyl neopentyl phosphonate, phenyl neopentyl phosphate, pentaerythritol diphenyl diphosphate, dicyclopentyl hypophosphate , Dineopentyl hypophosphite, phenylpyrocatechol phosphite, ethyl pyrocatechol phosphate and dipyrocatechol hypopositive phosphate.

Here, as the organic phosphorus compound, an aromatic phosphate ester monomer and an aromatic phosphate ester condensate are particularly preferred.

The nitrogen-based flame retardant as (C) is typically a compound containing a triazine skeleton, and is a component for further improving the flame retardancy as a flame retardant aid of a phosphorus-based flame retardant. Specific examples thereof include melamine, melam, melem, melon (product of deammonification of three to three molecules of melem at 600 ° C. or higher), melamine cyanurate,
Melamine phosphate, succinoguanamine, adipoguanamine, methylglutalogamine, melamine resin and BT resin can be mentioned, and melamine cyanurate is particularly preferred from the viewpoint of low volatility.

The inorganic flame retardant (C) includes aluminum hydroxide, magnesium hydroxide, dolomite, hydrotalcite, calcium hydroxide, barium hydroxide, basic magnesium carbonate, zirconium hydroxide, and tin oxide. Hydrates of inorganic metal compounds such as hydrates, aluminum oxide, iron oxide, titanium oxide, manganese oxide,
Metal oxides such as magnesium oxide, zirconium oxide, zinc oxide, molybdenum oxide, cobalt oxide, bismuth oxide, chromium oxide, tin oxide, antimony oxide, nickel oxide, copper oxide, tungsten oxide, aluminum,
Iron, titanium, manganese, zinc, molybdenum, cobalt,
Metal powders such as bismuth, chromium, nickel, copper, tungsten, tin, and antimony, and zinc borate, zinc metaborate, barium metaborate, zinc carbonate, magnesium carbonate, calcium carbonate, barium carbonate, and the like can be given. These may be used alone or in combination of two or more. Among them, those selected from the group consisting of magnesium hydroxide, aluminum hydroxide, basic magnesium carbonate, and hydrotalcite have particularly good flame retardant effects and are economically advantageous.

The fibrous flame retardant as (C) is a flame retardant used to prevent dripping of fire, and becomes fibrous at the time of addition or processing. Specific examples thereof include aramid fiber, polyacrylonitrile fiber, and fluororesin.

The novolak resin as the char-forming agent (C) is a phenol novolak resin obtained by condensing phenols and aldehydes in the presence of an acid catalyst such as sulfuric acid or hydrochloric acid.

In the present invention, the amount of (C) added is
(B) 0.001 to 100 parts by weight, more preferably 1 to 50 parts by weight, most preferably 3 to 20 parts by weight, very preferably 5 to 1 part by weight, per 100 parts by weight.
5 parts by weight.

In the present invention, if necessary, selected from aliphatic hydrocarbons, higher fatty acids, higher fatty acid esters, higher fatty acid amides, higher fatty alcohols, metal soaps, organosiloxane waxes, polyolefin waxes, and polycaprolactone. One or more release agents or processing aids (D) as flow improvers can be added.

The amount of (D) is preferably 0.01 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, and most preferably 1 to 5 parts by weight, per 100 parts by weight of (B). Department.

In the present invention, when light resistance is required, if necessary, an ultraviolet absorber, a hindered amine light stabilizer, an antioxidant, an active species trapping agent, a light shielding agent, a metal deactivator, or One or more light resistance improvers (E) selected from quenchers can be blended.
The amount of (E) is preferably 0.05 to 20 parts by weight, more preferably 0.1 to 1 part by weight, per 100 parts by weight of (B).
0 parts by weight, most preferably 1 to 5 parts by weight.

As a method for producing the resin composition containing (A) the flame retardant and (B) of the present invention, for example, a method in which (B) and (A) are mixed and melt-kneaded by an extruder; ) Was first melted, and then (A) the flame retardant of the present invention was added and melt-kneaded in the same extruder, or a master batch was prepared by mixing (B) with the (A) flame retardant of the present invention. Thereafter, there is a method of kneading the master batch with the remaining (B) or the remaining (A) flame retardant of the present invention or another flame retardant.

As a preferred example of the resin composition containing the flame retardants (A) and (B) of the present invention, (A) bisphenol A bis (triphenylsiloxane) or bisphenol A bis (triphenoxysiloxane) 0.1 to
100 parts by weight, (B) 100 parts by weight of aromatic polycarbonate alone or aromatic polycarbonate and styrene resin.

The polymer composition containing (A) a flame retardant and (B) of the present invention is obtained by, for example, melt-kneading the above-mentioned components with a commercially available single-screw extruder or twin-screw extruder. But if desired, a heat stabilizer other than the above in the composition,
Lubricants, fillers, reinforcing agents such as glass fibers, coloring agents such as dyes and pigments, and the like can also be added.

The composition thus obtained can be continuously molded for a long period of time using an injection molding machine or an extrusion molding machine, and the obtained molded article has flame retardancy, heat resistance and resistance to heat. The impact properties are excellent.

[0054]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the invention. In addition, the measurement in an Example and a comparative example was performed using the following method or a measuring device.

(1) Flame retardancy VB (Vertical Bur) conforming to UL-94
The self-extinguishing property was evaluated by the ning method. (1
/ 8 inch thickness test piece)

(2) Thermal stability (thermogravimetric balance test: TGA
Method) Using a Shimadzu thermal analyzer DT-40 manufactured by Shimadzu Corporation, the temperature was raised at 10 ° C./min under a nitrogen stream, and the 1% weight loss temperature was used as a measure of thermal stability.

The following components were used in the examples and comparative examples. (A) Silicon-based flame retardants Known techniques, for example, Chapter 17 of the “Silicone Handbook” [edited by Kunio Ito (Nikkan Kogyo Shimbun) (1990)]
Various silicon-based flame retardants were obtained according to the silicone production method.

(1) Bisphenol A bis (triphenoxysiloxane) 2 mol of triphenoxysilane chloride was reacted with 1 mol of bisphenol A according to a known production method to obtain a compound of the following formula (2). (Referred to as SI-1)

[0059]

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(2) Bisphenol A bis (triphenylsiloxane) 2 mol of triphenylsilane chloride was reacted with 1 mol of bisphenol A according to a known production method to obtain the following formula (3). (Referred to as SI-2)

[0061]

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(B) Silicon-based flame retardants other than this application (1) Polydimethylsiloxane (C-1) (2) Polydimethoxysiloxane (C-2) (3) Silica (C-3)

(C) Polymer (1) Aromatic polycarbonate [Bisphenol A type, trade name, Caliber 13 (referred to as PC), manufactured by Sumitomo Dow]

(2) Rubber-modified polystyrene (HIPS) Asahi Kasei Kogyo Co., Ltd. [polybutadiene / polystyrene (10/90: weight ratio) trade name Stylon (HIPS)
)]

(3) ABS resin (ABS) [Acrylonitrile / Polybutadiene / Styrene (24/20/56: weight ratio) trade name Styrac ABS (referred to as ABS)] manufactured by Asahi Kasei Kogyo Co., Ltd.

(4) Styrene-ethylene-butylene-styrene copolymer (SEBS) manufactured by Asahi Kasei Kogyo Co., Ltd. [trade name: Tuftec (referred to as SEBS)]

(5) Styrene-butadiene copolymer (S
B) manufactured by Asahi Kasei Kogyo Co., Ltd.

(6) Polyphenylene ether (PPE) manufactured by Asahi Chemical Industry Co., Ltd. (trade name: Zylon (referred to as PPE))

(7) Polypropylene (PP) Nippon Polychem Co., Ltd. (referred to as PP)

(8) Ethylene-octene copolymer (E
O) Dupont Dow elastomer [trade name Engage (E
O))

(9) Crosslinked EO-PP (TPV) Thermoplastic polypropylene dynamically crosslinked by a twin screw extruder using EO / PP = 50/50 (weight ratio) with an organic peroxide and divinylbenzene. Was used. (Referred to as TPV)

(D) Flame retardant aid (1) Metal salt of organic sulfonic acid Potassium diphenylsulfon-3-sulfonate (KSS) manufactured by UCB Japan

(2) Polytetrafluoroethylene (PT
FE) manufactured by Daikin Industries, Ltd. (referred to as PTFE)

Examples 1 to 21 Comparative Examples 1 to 3 The compositions shown in Table 1 were mixed in a Henschel mixer, and then a twin-screw extruder (40) having an injection port in the center of the barrel was used.
(mmφ, L / D = 47), and melt extrusion was performed at a temperature of 250 ° C. As the screw, a double screw having a kneading portion before and after the injection port was used.

From the composition thus obtained, a molded article was prepared by injection molding at a cylinder setting temperature of 240 ° C. and a mold temperature of 60 ° C. under the following conditions, and evaluated. The results are shown in Tables 1 and 2.

[0076]

[Table 1]

[0077]

[Table 2]

[0078]

The present invention relates to a silicon-based flame retardant capable of imparting excellent flame retardancy and thermal stability.
The flame retardant material obtained using the flame retardant of the present invention is a VTR,
Distribution boards, TVs, audio players, capacitors,
Household outlet, boombox, video cassette, video disc player, air conditioner, humidifier,
Household appliances such as electric warm air machines, chassis or parts, CD-ROM main frame (mechanical chassis),
OA for printers, faxes, PPCs, CRTs, word processing copiers, electronic cash registers, office computer systems, floppy disk drives, keyboards, types, ECRs, calculators, toner cartridges, telephones, etc.
Equipment housing, chassis or parts, connector, coil bobbin, switch, relay, relay socket, LE
D, variable condenser, AC adapter, FBT high pressure bobbin,
Electronic and electrical materials such as FBT case, IFT coil bobbin, jack, volume shaft, motor parts, instrument panel, radiator grill, cluster, speaker grill, louver, console box, defroster garnish, ornament, fuse box, relay case It is suitable for automotive materials such as connector shift tape, etc., and plays a large role in these industries.

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Claims (5)

[Claims] 1. A silicon-based flame retardant represented by the following formula (1). Embedded image (Wherein, R ^{1 to} R ⁶ each independently represent a monovalent C ₁ -C ₂₀ hydrocarbon group, Ar represents a divalent C ₆ -C ₂₀ aromatic group, and af represent 0 Or 1 and n is 1 or more expressed as a number average n value.) 2. R ^{1 to} R ⁶ are each independently a monovalent C ₆ -C
The silicon-based flame retardant according to claim 1, which is ₂₀ aromatic groups. R ^{1 to} R ⁶ are a phenyl group, Ar is 2,2′-bis (1,4-phenylene) propane, and a to f are simultaneously 0 or 1; ) Or the following formula (3). Embedded image Embedded image 4. A flame-retardant polymer composition comprising a polymer and the flame retardant according to claim 1. 5. A flame-retardant resin composition comprising a resin mainly composed of an aromatic polycarbonate and the flame retardant according to claim 1.